replacing Auth by C++ auth implementation (#802)

* lazy replacing FST(Firebase)CredentialsProvider by (Firebase)CredentialsProvider

* lazy replacing FSTUser by User

* adding error-code parameter to TokenListener

* actually use const user& instead of pointer; also add an error util

* add HashUser and pass into the unordered_map

* use User in test

* use c++ CredentialsProvider and subclass in test

* fix unit test

* use explicit capture in lambda instead of capture all by reference

* cache currentUser explicitly when reset sync engineer test driver

* objc object should be captured by value in lambda

* replacing Auth/FSTUser by C++ auth implementation

* address changes

* replacing FSTGetTokenResult by C++ Token implementation

* address changes

* fix unintentional change in merging

* patch the change in objc Auth up-stream

* somehow, the lambda-version of set-user-change-listener does not work... fallback to block

* address changes

* fix another const& v.s. dispatch bug

* fix more const& v.s. dispatch bug  zxu123 committed

* fix a bad sync line

* address changes

* address change

* address change

* fix upstream change from merge

* fix upstream changes

* Suggested fixes for cpp/port_auth (#846)

* Get rid of MockDatastore factory

This avoids the need to statically allocate (and leak) a credentials
provider

* Use absl::make_unique

std::make_unique technically does not exist until C++14.

* #include <utility> for std::move

* Use std::future for the initial user

* fix style

2 files changed, 9 insertions, 10 deletions

diff --git a/Firestore/Example/Tests/Integration/FSTDatastoreTests.mm b/Firestore/Example/Tests/Integration/FSTDatastoreTests.mm
index c38e8f3..4323ccd 100644
--- a/Firestore/Example/Tests/Integration/FSTDatastoreTests.mm
+++ b/Firestore/Example/Tests/Integration/FSTDatastoreTests.mm
@@ -23,7 +23,6 @@
 
 #import "Firestore/Source/API/FIRDocumentReference+Internal.h"
 #import "Firestore/Source/API/FSTUserDataConverter.h"
-#import "Firestore/Source/Auth/FSTEmptyCredentialsProvider.h"
 #import "Firestore/Source/Core/FSTFirestoreClient.h"
 #import "Firestore/Source/Core/FSTQuery.h"
 #import "Firestore/Source/Core/FSTSnapshotVersion.h"
@@ -41,11 +40,13 @@
 
 #import "Firestore/Example/Tests/Util/FSTIntegrationTestCase.h"
 
+#include "Firestore/core/src/firebase/firestore/auth/empty_credentials_provider.h"
 #include "Firestore/core/src/firebase/firestore/core/database_info.h"
 #include "Firestore/core/src/firebase/firestore/model/database_id.h"
 #include "Firestore/core/src/firebase/firestore/util/string_apple.h"
 
 namespace util = firebase::firestore::util;
+using firebase::firestore::auth::EmptyCredentialsProvider;
 using firebase::firestore::core::DatabaseInfo;
 using firebase::firestore::model::DatabaseId;
 
@@ -141,7 +142,7 @@ NS_ASSUME_NONNULL_BEGIN
 @implementation FSTDatastoreTests {
   FSTDispatchQueue *_testWorkerQueue;
   FSTLocalStore *_localStore;
-  id<FSTCredentialsProvider> _credentials;
+  EmptyCredentialsProvider _credentials;
 
   DatabaseInfo _databaseInfo;
   FSTDatastore *_datastore;
@@ -170,11 +171,9 @@ NS_ASSUME_NONNULL_BEGIN
       queueWith:dispatch_queue_create("com.google.firestore.FSTDatastoreTestsWorkerQueue",
                                       DISPATCH_QUEUE_SERIAL)];
 
-  _credentials = [[FSTEmptyCredentialsProvider alloc] init];
-
   _datastore = [FSTDatastore datastoreWithDatabase:&_databaseInfo
                                workerDispatchQueue:_testWorkerQueue
-                                       credentials:_credentials];
+                                       credentials:&_credentials];
 
   _remoteStore = [FSTRemoteStore remoteStoreWithLocalStore:_localStore datastore:_datastore];
 
diff --git a/Firestore/Example/Tests/Integration/FSTStreamTests.mm b/Firestore/Example/Tests/Integration/FSTStreamTests.mm
index 9105b74..6550368 100644
--- a/Firestore/Example/Tests/Integration/FSTStreamTests.mm
+++ b/Firestore/Example/Tests/Integration/FSTStreamTests.mm
@@ -22,16 +22,17 @@
 
 #import "Firestore/Example/Tests/Util/FSTHelpers.h"
 #import "Firestore/Example/Tests/Util/FSTIntegrationTestCase.h"
-#import "Firestore/Source/Auth/FSTEmptyCredentialsProvider.h"
 #import "Firestore/Source/Remote/FSTDatastore.h"
 #import "Firestore/Source/Remote/FSTStream.h"
 #import "Firestore/Source/Util/FSTAssert.h"
 
+#include "Firestore/core/src/firebase/firestore/auth/empty_credentials_provider.h"
 #include "Firestore/core/src/firebase/firestore/core/database_info.h"
 #include "Firestore/core/src/firebase/firestore/model/database_id.h"
 #include "Firestore/core/src/firebase/firestore/util/string_apple.h"
 
 namespace util = firebase::firestore::util;
+using firebase::firestore::auth::EmptyCredentialsProvider;
 using firebase::firestore::core::DatabaseInfo;
 using firebase::firestore::model::DatabaseId;
 
@@ -136,7 +137,7 @@ using firebase::firestore::model::DatabaseId;
   dispatch_queue_t _testQueue;
   FSTDispatchQueue *_workerDispatchQueue;
   DatabaseInfo _databaseInfo;
-  FSTEmptyCredentialsProvider *_credentials;
+  EmptyCredentialsProvider _credentials;
   FSTStreamStatusDelegate *_delegate;
 
   /** Single mutation to send to the write stream. */
@@ -155,7 +156,6 @@ using firebase::firestore::model::DatabaseId;
 
   _databaseInfo = DatabaseInfo(database_id, "test-key", util::MakeStringView(settings.host),
                                settings.sslEnabled);
-  _credentials = [[FSTEmptyCredentialsProvider alloc] init];
 
   _delegate = [[FSTStreamStatusDelegate alloc] initWithTestCase:self queue:_workerDispatchQueue];
 
@@ -165,14 +165,14 @@ using firebase::firestore::model::DatabaseId;
 - (FSTWriteStream *)setUpWriteStream {
   FSTDatastore *datastore = [[FSTDatastore alloc] initWithDatabaseInfo:&_databaseInfo
                                                    workerDispatchQueue:_workerDispatchQueue
-                                                           credentials:_credentials];
+                                                           credentials:&_credentials];
   return [datastore createWriteStream];
 }
 
 - (FSTWatchStream *)setUpWatchStream {
   FSTDatastore *datastore = [[FSTDatastore alloc] initWithDatabaseInfo:&_databaseInfo
                                                    workerDispatchQueue:_workerDispatchQueue
-                                                           credentials:_credentials];
+                                                           credentials:&_credentials];
   return [datastore createWatchStream];
 }